Public Veterinary Medicine: Public Health1690 Vet Med Today: Public Veterinary Medicine JAVMA, Vol 221, No. 12, December 15, 2002 R abies in the United States and other developed nations

1690 Vet Med Today: Public Veterinary Medicine JAVMA, Vol 221, No. 12, December 15, 2002

Rabies in the United States and other developednations is primarily a disease that affects and is

maintained by wildlife populations (Fig 1). During2001, wild animals accounted for more than 93% of allcases of rabies reported to the Centers for DiseaseControl and Prevention (CDC). Although the wildlifespecies most frequently reported rabid remain rac-coons, skunks, bats, and foxes, the relative contribu-tions of those species have continued to change inrecent decades (Fig 2) because of fluctuations in epi-zootics of rabies among animals infected with severaldistinct variants of the rabies virus.1

Vaccination campaigns and other rabies-controlprograms implemented during the 1940s and 1950scaused a substantial decline of rabies in domestic ani-mals in the United States and all but eliminated the cir-culation of canine variants of the rabies virus in dogs(Canis lupus, formerly known as C familiaris) by the1960s. Programs initiated to interrupt transmission of acanine variant that re-emerged in south Texas duringthe late 1970s and early 1980s have substantiallyreduced the spread of this variant, maintained in unvac-cinated dogs and coyotes (Canis latrans), as well as asecond canine variant found mainly in gray foxes(Urocyon cinereoargenteus) in west and central Texas.Regulations now in place in Texas and other states thatprohibit translocation of certain wild animal species forhunting and other restocking purposes have substan-tially reduced the likelihood of accidental introductionsof rabies virus variants into unaffected areas.1-3

Various public health activities have contributed toreduced transmission of rabies virus from terrestrialanimals to human beings. These activities have includ-ed vaccination of domestic animals, vaccination pro-grams targeting wildlife, and ongoing education pro-grams.4 However, a small but increasing number ofrabies cases in human beings have resulted from infec-

Rabies surveillance in the United States during 2001

From the Viral and Rickettsial Zoonoses Branch, Division of Viraland Rickettsial Diseases, National Center for Infectious Diseases,Centers for Disease Control and Prevention, 1600 Clifton Rd NE,Atlanta, GA 30333.

The authors thank the state and territorial health and agriculture depart-ments and laboratories for their contributions of rabies surveillancedata; the governments of Canada and Mexico for supplying sum-maries of rabies surveillance data; Karoyle Colbert, BiometricsActivity, Division of Viral and Rickettsial Diseases, National Center forInfectious Diseases, and Van Munn, Information ResourcesManagement Office, Office of Program Services, Office of the Director,Centers for Disease Control and Prevention, for assistance with graph-ics; and John P. O’Connor, Office of the Director, Division of Viral andRickettsial Diseases, National Center for Infectious Diseases, Centersfor Disease Control and Prevention, for editing and critical input.

John W. Krebs, MS; Heather R. Noll, MPH; Charles E. Rupprecht, VMD, PhD; James E. Childs, ScD

Summary: During 2001, 49 states and Puerto Rico reported7,437 cases of rabies in nonhuman animals and 1 case in ahuman being to the Centers for Disease Control andPrevention, an increase of < 1% from 7,364 cases in nonhu-man animals and 5 human cases reported in 2000. More than93% (6,939 cases) were in wild animals, whereas 6.7% (497cases) were in domestic species (compared with 93.0% inwild animals and 6.9% in domestic species in 2000). Thenumber of cases reported in 2001 increased among bats,cats, skunks, rodents/lagomorphs, and swine and decreasedamong dogs, cattle, foxes, horses/mules, raccoons, andsheep/goats. The relative contributions of the major groupsof animals were as follows: raccoons (37.2%; 2,767 cases),skunks (30.7%; 2,282), bats (17.2%; 1,281), foxes (5.9%;437), cats (3.6%; 270), dogs (1.2%; 89), and cattle (1.1%;82). Nine of the 19 states where the raccoon-associated vari-ant of the rabies virus has been enzootic reported decreasesin the numbers of rabid raccoons during 2001.

Among states with extensive wildlife rabies control pro-grams, Ohio reported (other than rabies in bats) 1 case of rabiesin a raccoon that was associated with the epizootic of rabies inraccoons and 1 case in a bovid that was infected with a bat vari-ant of the rabies virus, compared with no cases reported in anyterrestrial animals during 2000. Texas reported 1 case associat-ed with the dog/coyote variant of the rabies virus (comparedwith no cases in 2000) and 20 cases associated with the grayfox variant of the virus (a decrease of 50% from reported casesin 2000). Reports of rabid skunks in Massachusetts and RhodeIsland, states with enzootic raccoon rabies, exceeded reports ofrabid raccoons for the fifth consecutive year. A similar situationmay soon exist in the state of Maine (32 rabid skunks and 34rabid raccoons during 2001).

Nationally, the number of rabies cases in skunks during2001 increased by 2.7% over those reported in 2000. Texasreported the greatest number of rabid skunks ever documentedduring a single year by any state, as well as the greatest numer-ical increase in rabid skunks (778 cases in 2001, compared with550 in 2000; an increase of 228 cases, or 41.5%) and the largestoverall state total of rabies cases (1,043) during 2001. Arizonareported the greatest percentage increase in rabid skunks(247.1%), representing an increase from 17 rabid skunks in2000 to 59 in 2001. Nineteen of these cases were infected witha bat variant of the rabies virus, documenting a spillover eventfollowed by unprecedented detection of temporal enzootictransmission of a bat variant in a terrestrial species. The numberof cases of rabies reported in bats during 2001 (1,281 cases)increased 3.3% and surpassed the previous year’s record (1,240cases) as the largest number of reported cases ever recordedfor this group of mammals. Cases of rabies reported in dogs (89)and cattle (82) decreased by 21.9 and 1.2%, respectively; theseare the lowest numbers reported for rabid cattle and dogs sincethe dawn of national rabies record keeping (ca 1938). Cases incats (270) increased by 8.4% over those reported in 2000,whereas rabies among sheep and goats declined 70%, from 10cases in 2000 to 3 cases (goats only) in 2001. Rabies amonghorses and mules declined 1.9% (52 cases in 2000 to 51 casesin 2001). Reported cases of rabies in mongooses in Puerto Ricoincreased 18.6%, compared with the previous year (70 cases in2001 from 59 cases in 2000), whereas cases of rabies in dogsdeclined 15.3% (15 to 13). One case of rabies in a human beingreported by California during 2001 was the result of infectionwith a canine variant of the rabies virus acquired outside theUnited States.

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tion with variants of the rabies virus associated withbats,5,6 a wildlife group difficult to target for rabies con-trol by conventional methods. Prevention of rabiesresulting from infection with bat-associated variants isfurther challenged by the frequent absence of exposurehistories involving a bat bite. Since 1990, 24 of 26human cases of indigenously acquired rabies were asso-ciated, by genetic analysis, with variants of the rabiesvirus maintained by bats. Only 2 of these cases involveda report of a definite history of animal bite.2,5,6 Themost likely route of infection remains transmission bybite during contact with a bat that either was ignored orunnoticed and subsequently forgotten.

Rabies infections of terrestrial animals in mostareas of the United States occur in geographicallydefinable regions where virus transmission is primari-ly between members of the same species. Spilloverinfection from these species to other animal speciesoccurs, but rarely initiates sustained intraspecifictransmission. Once established, virus transmissionwithin a species can persist enzootically for decades,perhaps for centuries.

Variants of the rabies virus can be identified byreaction with panels of monoclonal antibodies7 or bypatterns of nucleotide substitution determined bygenetic analysis.1,8 The spatial boundaries of enzooticrabies in a reservoir species are temporally dynamic(Fig 3). Affected areas usually expand gradually

through transmission of the virus into previously unin-fected populations.9,10 Natural barriers such as moun-tain ranges or bodies of water that restrict animalmovements or result in low population densities canslow the spread of rabies. Nevertheless, unusual animaldispersal patterns and human-mediated translocationof infected animals have resulted in more rapid andunexpected introduction of rabies into new areas.1-3,8-10

Raccoons (Procyon lotor) have been recognized asa reservoir for rabies in the southeastern states sincethe 1950s. An outbreak that began during the late1970s in the mid-Atlantic states was attributed to thetranslocation by humans of infected raccoons from theSoutheast.11 Although previously identifiable as sepa-rate foci (prior to 1994), the mid-Atlantic and south-eastern foci have merged, and raccoon rabies is nowenzootic in all of the eastern coastal states as well asAlabama, Pennsylvania, Vermont, West Virginia, andpossibly Ohio.

At least 3 variants of rabies virus are responsiblefor disease in skunks (primarily Mephitis mephitis) inCalifornia and the north central and south centralstates. A long-standing reservoir for rabies virus existsin red and arctic foxes (Vulpes vulpes and Alopex lago-pus, respectively) in Alaska. Rabies spread during the1950s to affect foxes across Canada and, intermittent-ly, foxes in adjoining areas of the New England states.Rabies persists in foxes in Alaska, although reports ofrabid foxes have declined in Canada. Two variants ofrabies virus are present in geographically limited pop-ulations of gray foxes (U cinereoargenteus) in Arizonaand Texas. Enzootic rabies among canids in southernTexas is the result of long-standing interaction betweenunvaccinated domestic dogs and coyotes at the Texas-Mexico border.12

The use of long-term, widespread population-reduction programs to control rabies among wild terres-trial carnivores is not desirable nor has such an under-taking been successful in North America or elsewhere.Programs in Europe and southeastern Canada haveinstead used modified-live or recombinant virus vac-cines for oral immunization of free-ranging wildlifereservoir species to control the disease. During the past2 decades, more than 100 million doses of vaccine-ladenbait have been distributed over 6 million square kilome-ters in Europe,13 with promising results for controlling

Figure 1—Cases of animal rabies in the United States, by year,1955 to 2001.

Figure 2—Cases of rabies in wild animals in the United States,by year and species, 1955 to 2001.

Figure 3—Distribution of major terrestrial reservoirs of rabies inthe United States.



the disease in red foxes. The use of oral vaccination inSwitzerland during the past 20 years resulted in a decla-ration of rabies-free status in 1998, and a similar decla-ration was made by France as of the end of 2000.14

Substantial decreases of reported cases of rabies in foxpopulations in southern Ontario strongly support theobservation that variants of the rabies virus associatedwith red foxes may be eliminated by vaccination.Distribution of an oral vaccinia-rabies glycoprotein (V-RG) recombinant vaccine targeting raccoons in the east-ern United States15-17 and gray foxes and coyotes inTexas18 has shown promise as a complement to tradi-tional rabies-control methods. However, products usedin oral vaccination programs are self-replicating, and theunintentional exposure of nontarget species, includinghuman beings, must be minimized and monitored.19,20

Overlaying the patterns of rabies virus mainte-nance among terrestrial mammals are multiple inde-pendent reservoirs for rabies virus in several species ofinsectivorous bats. Rabies virus transmission amongbats appears to be primarily intraspecific, and distinctvirus variants can be identified for different bat species.In contrast to maintenance cycles in terrestrial animals,however, the greater mobility of bats precludes defini-tive range mapping of different variants other than asthe geographic ranges of the implicated host batspecies. Because bat species known to be reservoirs forrabies virus are found in all areas of the continentalUnited States, every state except Hawaii is consideredenzootic for rabies. Although transmission of rabiesvirus from bats to terrestrial mammals occurs, there isno evidence that such spillover transmission results infrequent, sustained, independent, intraspecific cyclesamong terrestrial animals. Genetic analysis indicatesnet differences of 15 to 20% between rabies virus RNAsequences in bats, compared with those in terrestrialmammals. Thus, instances of spillover transmission ofrabies virus from bats are readily detectable, as wouldbe sustained transmission of a bat-associated variant ina terrestrial mammal population.

This report is prepared annually to inform veteri-narians and public health officials of the current statusof rabies in the United States. Information is providedon the geographic distribution of rabies and long- andshort-term temporal patterns for reported cases ofrabies in various species. Long-term trends for report-ed cases of rabies in animals in the United States aregenerated by examining reports starting in 1955.Short-term trends are determined by comparing report-ed cases from 2001 with those from 2000 and by exam-ining seasonal patterns for selected species.

Summaries of 2001 surveillance data are providedfor Canada and Mexico because of common bordersand frequent travel between the United States andthese countries. A brief update on cases of rabies andother related activities reported to CDC during 2002 isalso included.

Collection of DataData collection procedures were similar to those

described previously.2 Between Jan 1 and Dec 31, 2001,all 50 states, New York City, and Puerto Rico reportedthe number of cases of rabies in animals to CDC. States

submitted data monthly on the number of cases bycounty of origin and type of animal. States report mostterrestrial mammals by using the common names ofthese animals (usually identifiable to the taxonomiclevel of genus and often to the level of species); how-ever, bats are frequently reported only to the taxonom-ic level of order (ie, Chiroptera = bats). Several statesreported data by using the Public Health LaboratoryInformation System or the Laboratory InformationTracking System.21,22 All year-end totals were con-firmed by telephone verification with state or territori-al health department officials. Data from Canada wereobtained from Dr. Carolyn Inch, Animal Health andProduction Division, Canadian Food InspectionAgency, and data from Mexico were obtained from Dr.Oscar Velazquez Monroy, Director General del Centrode Vigilancia Epidemiologica, Secretaria de Salud,Mexico.

Diagnoses in animals suspected of having rabieswere made by direct immunofluorescent antibodystaining of rabies viral antigen in brain material sub-mitted to the state or local health departments. Virusisolation in neuroblastoma cell cultures of mice andnucleic acid detection via reverse transcriptase (RT)-polymerase chain reaction (PCR) assays were used toconfirm some cases.

Rabies in Wild AnimalsWild animals accounted for more than 93% of the

7,437 reported cases of rabies in 2001 (Fig 1). The6,939 cases reported among wildlife in 2001 represent-ed a 1.2% increase over the 6,855 cases reported in2000 (Table 1). Raccoons continued to be the most fre-quently reported rabid wildlife species (37.2% of allanimal cases during 2001), followed by skunks(30.7%), bats (17.2%), foxes (5.9%), and other wildanimals, including rodents and lagomorphs (2.3%).Numbers of reported cases in bats and skunksincreased 3.3 and 2.7%, respectively, over 2000 totals,whereas cases in raccoons and foxes decreased 0.4 and3.5%, respectively.

Raccoons—The 2,767 cases of rabies in raccoons(P lotor) reported in 2001 marked the fifth consecutiveyear of decreased numbers in this species (Fig 2 and 4).Decreases in numbers of rabid raccoons during 2001were reported by 9 of the 19 eastern states in whichraccoon rabies has been enzootic, including Alabama(57.7% decrease; 52 cases in 2000 to 22 in 2001),Connecticut (10.1%; 149 to 134), Delaware (21.2%; 33to 26), Georgia (0.4%; 229 to 228), Maine (53.4%; 73to 34), New Jersey (9.8%; 132 to 119), North Carolina(0.5%; 388 to 386), South Carolina (27.3%; 110 to 80),and Virginia (12.2%; 328 to 288) (Fig 4 and 5; Table1).2,8-11,15,23 Ten states with enzootic raccoon rabiesreported increases in numbers of rabid raccoons,including Florida (35.4% increase), Maryland (16.9%),Massachusetts (7.9%), New Hampshire (33.3%), NewYork (1.2%), Ohio (no cases in 2000 to 1 case in 2001),Pennsylvania (5.6%), Rhode Island (175%), Vermont(11.1%), and West Virginia (24.7%) as well as NewYork City (222%).

The states of the northeastern/mid-Atlantic focus



of the epizootic, consisting of Connecticut, Delaware,Maine, Maryland, Massachusetts, New Hampshire,New Jersey, New York, Ohio, Pennsylvania, RhodeIsland, Vermont, Virginia, West Virginia, the District ofColumbia, and New York City, accounted for 69.1%(1,912 cases) of the total rabies cases in raccoons in2001, whereas the southeastern states of Alabama,Florida, Georgia, North Carolina, and South Carolina

reported 30.6% (846 cases) of the total cases in rac-coons.

Ohio reported a single case of rabies in a raccooninfected with the raccoon variant of the rabies virus.Rabid raccoons reported by Texas (9 cases) were theresult of apparent spillover infection with variants ofthe rabies virus other than that associated with rac-coons (usually the gray fox variant or the south central

Domestic animals Wild animals

State All Horses/ Sheep/ Other Rodents and Other Human Change‡ City animals Domestic Wild Dogs Cats Cattle mules goats Swine domestic Skunks Foxes Bats Raccoons lagomorphs* wild† beings 2000 (%)

7,437 497 6,939 89 270 82 51 3 2 0 2,282 437 1,281 2,767 56 116 1 7,369 0.92AL 66 6 60 3 3 1 6 31 22 80 –17.50AK 48 3 45 3 45 35 37.14AZ 129 0 129 59 6 55 9n 101 27.72 AR 32 1 31 1 28 3 32 0.00 CA 322 2 319 1 1 151 2 166 1 274 17.52CO 32 0 32 32 67 –52.24CT 242 8 234 6 2 77 5 14 134 3a 1p 273 –11.36DC 9 0 9 1 8 14 –35.71DE 39 2 37 2 3 6 2 26 61 –36.07FL 209 18 191 1 16 1 35 21 130 1b 4q 161 29.81GA 402 35 367 6 26 1 1 1 41 55 37 228 6r 358 12.29HI 0 0 0 0 —ID 29 0 29 28 1s 10 190.00IL 24 0 24 24 22 9.09IN 15 0 15 15 14 7.14IA 85 25 60 2 10 10 3 28 1 31 81 4.94KS 100 24 76 2 11 7 4 69 2 5 97 3.09KY 30 5 25 3 1 1 15 2 8 21 42.86LA 10 1 9 1 5 4 4 150.00ME 85 5 80 3 1 1 32 5 8 34 1t 139 –38.85MD 505 26 479 1 23 1 1 42 38 27 366 6c 413 22.28MA 279 11 268 1 8 1 1 132 10 32 82 9d 3u 276 1.09MI 47 4 43 1 1 2 2 41 68 –30.88MN 47 10 37 4 1 2 3 24 13 99 –52.53MS 4 0 4 4 1 300.00MO 40 3 37 1 1 1 5 1 31 50 –20.00MT 36 5 31 1 3 1 17 14 64 –43.75NE 12 4 8 2 1 1 2 6 3 300.00NV 5 0 5 5 10 –50.00NH 25 2 23 1 1 5 8 8 2e 23 8.70NJ 200 19 181 17 2 16 5 37 119 4f 219 –8.68NM 15 1 14 1 2 12 21 –28.57NY 783 43 740 2 31 6 3 1 164 36 109 415 16g 823 –4.86NYC 38 1 37 1 4 4 29 18 111.11NC 571 20 551 6 13 1 73 56 31 386 1h 4v 571 0.00ND 42 14 28 2 3 6 3 27 1w 118 –64.41OH 52 1 51 1 50 1 52 0.00OK 60 11 49 2 1 6 1 1 45 3 1x 58 3.45OR 4 0 4 4 9 –55.56PA 441 46 395 4 33 7 2 68 34 43 244 6i 415 6.27PR 98 28 70 13 6 2 6 1 70y 80 22.50RI 72 1 71 1 39 3 6 22 1j 60 20.00SC 143 9 134 4 4 1 25 25 4 80 181 –20.99SD 58 13 45 1 4 7 1 34 11 96 –39.58TN 106 2 104 2 93 11 107 –0.93TX 1,043 41 1,002 16 13 7 5 778 15 194 9 6z 830 25.66UT 15 0 15 15 10 50.00VT 62 0 62 11 4 3 40 4k 57 8.77VA 502 31 471 4 20 5 2 116 34 23 288 3m 7aa 574 –12.54WA 22 0 22 22 23 –4.35WV 142 7 135 1 6 23 3 11 96 2bb 115 23.48 WI 20 7 13 5 2 1 12 10 100.00WY 40 2 38 1 1 27 1 10 71 –43.66

% 2001§ 100.00 6.68 93.30 1.20 3.63 1.10 0.69 0.04 0.03 0.00 30.68 5.88 17.22 37.21 0.75 1.56 0.01Total 2000II 7,369 509 6,855 114 249 83 52 10 0 1 2,223 453 1,240 2,778 52 109 5% change‡ 0.92 –2.36 1.23 –21.93 8.43 –1.20 –1.92 –70.00 –100.00 2.65 –3.53 3.31 –0.40 7.69 6.42 –80.00

*Rodents and lagomorphs include: a3 groundhogs; b1 beaver; c5 groundhogs, 1 chipmunk; d8 groundhogs, 1 rabbit; e2 groundhogs; f4 groundhogs; g1 beaver, 3 rabbits, 12 groundhogs; h1 rabbit; i5 groundhogs, 1 beaver; j1 groundhog; k4 groundhogs; m3 groundhogs. †Other wild includes: n1 badger, 4 bobcats, 4 coyotes; p1 coyote; q1 bobcat, 3 otters; r5 bobcats, 1 otter; s1 bob-cat; t1 bobcat; u2 coyotes, 1 otter; v4 bobcats; w1 badger; x1 opossum; y70 mongooses; z1 ringtail, 5 bobcats; aa6 bobcats, 1 deer; bb1 opossum, 1 bobcat. ‡Percentage change from 2000.§Percentage of all rabid animals in 2001. II2000 total by species.

Table 1—Cases of rabies, by state and category, in the United States and Puerto Rico during 2001



skunk variant). During 2001, with the exception of therabid raccoon reported by Ohio, states west of the OhioRiver in the North and west of the AppalachianMountains in the South did not report any cases ofrabies thought to be associated with the variant of therabies virus that is epizootic in raccoons during 2001.

Skunks—The 2,282 cases of rabies in skunks(mainly M mephitis) in 2001 reported by 36 states rep-resented a 2.7% increase over those reported in 2000(Fig 6). Thirteen states reported increases in numbersof rabid skunks. Texas reported the greatest number ofrabid skunks ever reported during a single year by anystate and the greatest numerical increase in rabidskunks (778 cases in 2001, compared with 550 in 2000;an increase of 228 cases or 41.5%). Arizona reportedthe largest percentage increase (247.1%; 59 cases in2001, compared with 17 cases in 2000) in the numberof rabid skunks. Louisiana (150%; 2 cases in 2000 to 5cases) was the only other state that reported an increaseof > 100% in 2001. Alabama reported 1 case of rabies ina skunk in 2001, but none in 2000. Twenty-one statesand New York City reported decreases in numbers ofrabid skunks in 2001. Delaware (72.7%; 11 cases to 3cases), Minnesota (60.7%; 61 to 24), Montana (54.1%;37 to 17), New Mexico (77.8%; 9 to 2), North Dakota(64.9%; 77 to 27), and Wyoming (51.8%; 56 to 27)

reported decreases of > 50%, compared with casesreported in 2000. Florida (1 case) and Michigan (2)reported rabid skunks in 2000, but not in 2001. Stateswhere the raccoon-associated variant of the rabies virusis enzootic reported 38.2% (872/2,282) of the cases ofrabies in skunks, the majority of which were presum-ably the result of spillover transmission of virus fromraccoons. Massachusetts (132 cases) and Rhode Island(39 cases) each reported more rabid skunks than rabidraccoons for the fifth consecutive year.

Bats—Rabies in bats accounted for 17.2% of allcases of rabies in animals reported in 2001. The 1,281cases were the largest number ever reported and repre-sented a 3.3% increase over the total reported in 2000.Rabies in bats is widely distributed throughout theUnited States, with cases reported from 47 of the 48 con-tiguous states (Fig 7). During 2001, Texas reported thelargest number of cases (194), followed by California(166) and New York (113 [includes 4 cases reported byNew York City]). Nine states (Colorado, Idaho, Illinois,Indiana, Mississippi, Nevada, Oregon, Utah, andWashington) reported rabies in bats, but not in terrestri-al mammals. Alaska, Hawaii, North Dakota, and PuertoRico did not report any cases of rabies in bats.

Of the bats positive for rabies virus, 58.1%(744/1,281) were identified beyond the taxonomiclevel of order (22 to genus, 722 to species). Amongbats identified to species level, 47.1% (340/722) wereEptesicus fuscus, the big brown bat; 28.3% (204/722)were Tadarida brasiliensis, the Brazilian (Mexican) free-tailed bat; 5.5% (40/722) were Lasiurus cinereus, thehoary bat; 4.3% (31/722) were L borealis, the red bat;3.7% (27/722) were Myotis lucifugus, the little brownbat; 3.0% (22/722) were Lasionycteris noctivagans, thesilver-haired bat; 1.7% (12/722) were M yumanenis, theYuma bat; 1.7% (12/722) were Pipistrellus hesperus, thewestern pipistrelle; and 1.2% (9/722) were P subflavus,the eastern pipistrelle. Unspeciated bats of the genusMyotis (3.0% [22/744]) and 11 other species (con-tributing < 3.5% [25/722] to the total, with no indi-vidual species in this latter group contributing > 1.0%)accounted for the remaining rabid bats. Not all stateswere able to speciate bats, nor did all states report totalnumbers of bats tested for rabies.

Figure 4—Changes in number of cases of rabies in raccoons inthe mid-Atlantic and northeastern states, 2000 to 2001. Dot sizeis proportional to the number of cases in the county.

Figure 5—Reported cases of rabies in raccoons, by county,2001.

Figure 6—Reported cases of rabies in skunks, by county, 2001.



Foxes—Foxes (mainly V vulpes) accounted for5.9% of all cases of rabies in animals reported in 2001.The majority of cases of rabies in foxes (360/437) werereported by states affected by the raccoon-associatedvariant of the rabies virus (Fig 8). Alaska (45 cases),Maryland (38), and North Carolina (56) reportedincreases of 13, 10, and 12 cases, respectively, over2000. Arizona (6 cases), New York (36), Virginia (34),and Texas (15) reported decreases of 9, 9, 16, and 26cases, respectively. Most cases of rabies in foxes report-ed by eastern states were probably caused by the rabiesvirus variant associated with raccoons, with the possi-ble exception of Maine, New York, and Vermont.Rabies in gray foxes in Arizona and Texas is usually theresult of infection with gray fox variants unique toindependent gray fox reservoirs in each of those states,as determined by antigen typing and genetic analysis.Iowa (1 case), Missouri (1), Vermont (4), andWyoming (1) reported rabid foxes in 2001 but did notreport rabid foxes in 2000, whereas New Hampshireand Oregon reported rabid foxes in 2000, but reportednone in 2001.

Other wild animals—Puerto Rico reported 70rabid mongooses (Herpestes auropunctatus) during2001, an 18.6% increase over those reported in 2000(Fig 9). Other wildlife in which rabies was reportedincluded 49 groundhogs (Marmota monax), 28 bob-cats (Lynx rufus), 7 coyotes (C latrans), 5 otters(Lontra canadensis), 5 rabbits (Oryctolagus cuniculus),3 beavers (Castor canadensis), 2 badgers (Taxideataxus), 2 opossums (Didelphis virginiana), 1 chip-munk (Tamias striatus), 1 deer (Odocoileus virgini-anus), and 1 ringtail (Bassariscus astutus). All cases ofrabies in rodents and lagomorphs (primarily ground-hogs; 47/56 cases) were reported by states in whichrabies is epizootic in raccoons.24 No cases of rabies incoyotes were associated with enzootic transmission ofthe dog/coyote variant of the rabies virus in regions ofsouthern Texas (Fig 9).

Rabies in Domestic AnimalsDomestic species accounted for 6.7% of all rabid

animals reported in the United States in 2001. Thenumber of domestic animals reported rabid in 2001

(497) represented a 2.4% decrease from the totalreported in 2000 (Fig 10). Cases of rabies reported indogs and cattle decreased 21.9 and 1.2%, respectively,compared with totals reported in 2000, whereas reportsof rabies in cats increased 8.4%. Numbers reported fordogs and cattle represent record lows for both speciessince the dawn of national rabies record keeping (ca1938). Reported cases of rabies in cats were more than

Figure 7—Reported cases of rabies in bats, by county, 2001.Figure 8—Reported cases of rabies in foxes, by county, 2001.

Figure 9—Reported cases of rabies in “other wild” category ofTable 1, by county and municipio (Puerto Rico), 2001.

Figure 10—Cases of rabies in domestic animals in the UnitedStates, by year, 1955 to 2001.



3 times as numerous as those reported in dogs or cat-tle. Pennsylvania reported the largest number of rabiddomestic animals (46 cases; predominantly in cats),followed by New York (43, and 1 case reported by NewYork City) and Texas (41).

Cats—Two hundred fourteen of the 270 cases ofrabies in cats were reported from states where the rac-coon-associated variant of the rabies virus is present(Fig 11). Remaining cases were reported principallyby Central Plains states, where most cases were pre-sumably the result of spillover from rabid skunks, orfrom rabid foxes in Texas. Ten states reported > 10cases of rabies in cats (Pennsylvania, 33; New York, 31[and 1 in New York City]; Georgia, 26; Maryland, 23;Virginia, 20; New Jersey, 17; Florida, 16; NorthCarolina, 13; Texas, 13; and Kansas, 11). Nineteenstates and the District of Columbia did not report anyrabid cats.

Dogs—Texas (16 cases) and Puerto Rico (13cases) reported the largest numbers of cases of rabies indogs by individual states or territories in 2001. Texasreported 1 case of rabies in a dog that was associatedwith the dog/coyote variant of the rabies virus evidentin south Texas (Fig 12). Georgia (6 cases) and NorthCarolina (6) were the only other states that reported >5 cases of rabies in dogs in 2000. Twenty-four states,the District of Columbia, and New York City did notreport any rabid dogs.

Other domestic animals—The number of casesof rabies in cattle decreased from 83 in 2000 to 82 in2001 (Fig 13), replacing the previous year’s record-low number for cattle, and distribution mirroredthat of rabid skunks in the central and midwesternstates (Fig 6 and 13) and raccoons in the mid-Atlantic/northeastern region (Fig 5 and 13). Iowa(10 cases), Kansas (7), South Dakota (7), and Texas(7) reported the largest numbers of rabid cattle. Noother state reported > 6 cases of rabies in cattle. The51 cases of rabies reported in horses, donkeys, andmules in 2001 represented a single-digit declinefrom the 52 cases reported during 2000. Otherreported cases of rabies in domestic animals includ-ed 3 goats and 2 swine.

Seasonal TrendsThe frequency of reported cases of rabies in rac-

coons peaked in April, followed by a lesser peak inSeptember and a December low (Fig 14). The frequen-cy of reporting for rabid skunks peaked in March, fol-lowed by a decline into the summer months prior to asecond broad but lower peak in October. Reports ofrabid bats showed a sharp August peak. Though large-ly flat, the largest numbers of rabid foxes were report-ed from May to July, followed by a gradual decline to alow in November.

Reporting of rabies in cats was highest during thesummer and, except for a slight decline in July, wasremarkably consistent from May through September.Reports of rabies cases in dogs and cattle were highestduring spring and fall, probably reflecting peak inter-action with rabid wildlife species, but otherwiseshowed no clear patterns (Fig 14 and 15).

Rabies in Human BeingsCalifornia reported a case of rabies in a 72-year-old

male resident of San Diego County during 2001.2,a Thecase was discovered retrospectively via ongoing activi-ties associated with that state’s unexplained encephali-tis surveillance program. The patient was admitted toan emergency room on Jan 24, 2001, with low-grade

Figure 11—Reported cases of rabies in cats, by county andmunicipio (Puerto Rico), 2001.

Figure 12—Reported cases of rabies in dogs, by county andmunicipio (Puerto Rico), 2001.

Figure 13—Reported cases of rabies in cattle, by county andmunicipio (Puerto Rico), 2001.



fever and several days of generalized weakness accom-panying complaints that may have begun approximate-ly 5 days earlier. During his 11-day hospitalization, thepatient’s status deteriorated to unexplained progressiveencephalopathy, decreased mental status, flaccid paral-ysis, respiratory failure, coma, and eventually death onFebruary 4. The California Viral and RickettsialDisease Laboratory performed fluorescent antibodytests on sera that had been collected as indicated forthe state’s unexplained encephalitis surveillance pro-gram. Sera collected 4 days and 1 day prior to thepatient’s death were each positive for rabies antibodies.No brain specimens were available for testing. TheCDC tested a throat swab from the patient by using RT-PCR and found it to be positive for rabies virus; thevariant of the virus identified was consistent with thosefound in rabid Philippine dogs. The patient had movedfrom the Philippines to San Diego in 1997 and traveledback to the Philippines for a visit between Mar 11 andMay 13, 2000. Family members reported no history ofa recent known animal bite or significant animal expo-sure, although such a bite during his more recent visitor in the past was the most plausible explanation forthe patient’s infection.

Rabies in Canada and MexicoCanada reported 441 laboratory-confirmed and 4

clinically diagnosed cases of rabies in domestic andwild animals in 2001. This number represented a

33.6% decrease from the 670 cases reported in 2000.Most of the decrease was attributable to a substantialdecline in numbers of reported cases of rabies inskunks in the provinces of Manitoba andSaskatchewan. Reported cases in skunks decreased by69.1% (125 cases in 2001, compared with 404 cases in2000) and accounted for 28.1% (125/445) of all rabidanimals reported in 2001. Reported cases of rabies inraccoons increased 89.4% from 47 cases in 2000 to 89cases in 2001, making raccoons the third most com-monly reported rabid animal. Reported cases of rabiesin raccoons in Canada have increased for the past 4consecutive years. Reported cases of rabies in batsincreased 43.1% (103 cases in 2001, compared with 72cases in 2000) and accounted for 23.1% (103/445) ofall reported cases of rabies. Other species that con-tributed substantially to the 2001 total included cattle(5.8%), foxes (14.2%), dogs (3.6%), and equids(2.3%). Canada did not report any cases of rabies inhuman beings during 2001.

Mexico reported 354 laboratory-confirmed casesof rabies in domestic and wild animals during 2001.This total represented a 36.8% decrease from the 560cases reported in 2000. Dogs accounted for 33.1%(117/354) of reported cases of rabies, a decrease of 52%from 2000 (244 cases). The other reported rabid ani-mals included 190 cattle, 11 skunks (several species),7 equids, 7 sheep, 6 goats, 4 bats, 4 wild cats (presum-ably bobcats [L rufus]), 3 foxes, 2 coyotes (C latrans),2 swine, and 1 puma (Puma concolor). Seven cases ofrabies were reported in human beings, a 40% increaseover 2000 (5 cases). Source animals implicated in theexposure of the human beings were reported as fol-lows: bats, 2 cases; skunk, 2 cases; dog, 1 case; puma,1 case; and 1 case for which no animal could be impli-cated.

DiscussionStates have different algorithms for submission of

specimens for rabies testing, and levels of surveillancevary. The predominantly passive nature of rabies sur-veillance and lack of estimates of animal populationsizes dictate that prevalence or incidence of rabies can-not be determined for most species. Many rabid ani-mals are never observed and go untested and undetect-ed.25 Thus, reported cases of rabies provide only anindex of the magnitude of the disease and do not indi-cate the extent of viral infection among wildlife ordomestic animals of any region. Cases detailed in thisreport include only those cases of rabies that were lab-oratory confirmed and reported to CDC by state andterritorial health departments.

The number of cases of rabies in raccoons declinedfor the fifth consecutive year. Although raccoons con-tinued to account for the highest percentage (37.2%) ofrabies cases reported among animals in the UnitedStates in 2001, this ratio was the lowest percentagecontribution by this species since 1990 (Fig 2).Enzootic transmission of rabies among raccoons wasapparent in 19 states and the District of Columbia in2001 (a single case of rabies in a raccoon infected withthe raccoon variant of the rabies virus was reported byOhio during 2001). States in the affected area reported

Figure 14—Cases of rabies in wild animals in the United States,by month, 2001.

Figure 15—Cases of rabies in domestic animals in the UnitedStates, by month, 2001.



99.7% (2,758/2,767) of all documented cases of rabiesin raccoons and accounted for 65.4% (4,867/7,437) ofthe total cases of rabies reported in the United Statesduring 2001. Periodic increases in numbers of report-ed cases of rabies in states where the disease is enzoot-ic among raccoons can occur when populations of rac-coons, decimated by a previous epizootic, again reachdensities sufficient to support transmission of rabiesvirus.9,10

The first field release of the V-RG vaccine in theUnited States began during 1990.26 The V-RG vaccinewas conditionally licensed in April 1995 and was fullylicensed in April 1997. Vaccine distribution in eachstate remains limited to authorized state or federalrabies-control programs. Interventions using the V-RGvaccine distributed within baits to vaccinate wild rac-coons to prevent or slow the dissemination of rabiescontinue in a number of states and are being undertak-en by additional states. The efficacy of these programsremains under assessment in Florida (Pinellas County),eastern Massachusetts (Cape Cod),17 Maryland, south-ern New Jersey (Cape May),16 New York, Ohio,Pennsylvania, Vermont, Virginia, and West Virginia.

During 2001, multiple state agencies, the USDA,and CDC collaborated on a program to establish an“immune barrier,” using oral rabies vaccine (ORV) tospan the distance from the shores of Lake Erie inOhio, Pennsylvania, and New York to the Gulf ofMexico in Alabama. Ohio rebaited a 6-county areaincluding 4 counties bordering Pennsylvania duringthe spring and expanded this area further to the southto include 3 additional counties during the fall(www.odh.state.oh.us/ODHPrograms/ZOODIS/Rabies/Pubs/ORVHIS.PDF; accessed Oct 16, 2002).b Alsoduring the fall of 2001, ORV baits were distributedover a 19-mile-wide corridor along the shore of LakeErie in Pennsylvania from the Ohio border to the NewYork border, thereby expanding and interconnectingthe existing ORV barriers in these 3 states. The ORVbaits were also distributed in 22 West Virginia coun-ties along a region of the Appalachian ridge thought tobe ahead of the raccoon rabies enzootic as determinedby active rabies surveillance. The sum of these ORVprograms during 2001 formed the northern portion ofa continuous immune corridor, augmented by geo-graphic barriers (lakes, rivers, and mountains),extending from the shore of Lake Erie through thestate of West Virginia. This “cordone sanitaire” will beextended further south and moved eastward over timein an attempt to reduce the area of enzootic rabies inraccoons. Concerns regarding vaccine safety, efficacy,ecologic impact, and physical bait variables, whichwere raised during earlier trials, continue to beassessed.19,20,27-29

Although the total number of rabid skunks report-ed in 2001 was 2.7% greater than that reported in2000, only 13 states reported increases, compared with21 that reported decreases (4 reported no change).Only Arizona and Louisiana reported increases of >100%, and approximately half of the increase reportedby Arizona was the result of active surveillance thatresulted from the discovery of a skunk found to beinfected with a bat variant of the rabies virus. Nineteen

rabid skunks in the Phoenix area were infected with abat variant of the rabies virus, documenting a rarespillover event followed by the unprecedented discov-ery of temporal enzootic transmission of a bat variantin a terrestrial species. Other than Arizona (up 42cases), only California (up 53 cases) and Texas (up 228cases) reported numerical increases of any great conse-quence. Only 4 of the remaining 10 states reportedincreases of more than 5 rabid skunks over thosereported in 2000. Michigan, a state that reported anincrease of 950% in rabid skunks (probably because ofactive surveillance) in 1999, did not report any cases ofrabies in skunks during 2001.

Rabid skunks outnumbered reported rabid rac-coons in Massachusetts (132 cases in skunks, com-pared with 82 in raccoons) and Rhode Island (39 casesin skunks, compared with 22 cases in raccoons) for thefifth consecutive year. This trend further fueled con-cerns that skunks may be involved in enzootic trans-mission of the raccoon variant of the rabies virus.Analyses comparing data from these states and datafrom other states where rabies in raccoons is enzootichave thus far failed to demonstrate evidence of adapta-tion of the raccoon variant of the rabies virus to main-tenance by and circulation in regional skunk popula-tions.c

Cases of rabies in foxes decreased 3.5%. Because ofcontrol of rabies resulting from the red fox variant ofthe rabies virus in Canada and New England, mostcases of rabies in foxes reported by eastern states wereprobably caused by the rabies virus variant associatedwith raccoons. Rabies in gray foxes in Arizona andTexas is usually the result of infection with gray foxvariants found in each of those states; however, Texashas had considerable success in reducing infectionsresulting from the Texas gray fox variant of the rabiesvirus via the use of an ORV in baits targeted at grayfoxes.d Thirteen states reported decreases in cases ofrabies in foxes; Texas (41 cases in 2000 to 15 in2001;–63.4%) and Virginia (50 cases to 34; –32%)reported decreases of more than 9 cases. In contrast, 15states reported increases in numbers of rabid foxes,although increases were usually small. Alaska,Maryland, and North Carolina reported increases of 13,10, and 12 cases, respectively; only New Jersey (2 casesin 2000 to 5 in 2001) reported an increase of > 100%.

The occurrence of rabies in various species of batsfluctuates by geographic region. The continued andincreasing association of bat rabies virus variants withhuman rabies infections in the United States duringrecent years has brought increased publicity andchanges in public health recommendations proposedwhen rabies exposures involving bats may haveoccurred.30,31 Rabies among rodents and lagomorphsreflects spillover infection, predominantly from region-al terrestrial reservoir species. Reported cases amongrodents occur primarily in groundhogs in areas of thecountry affected by the raccoon-associated variant ofthe rabies virus.24 Rabies is occasionally reported inother large members of this group such as beavers.32

Large species of rodents and lagomorphs, or those keptin outdoor cages, may become infected and survivelong enough to pose a risk to other species. Rabies is



seldom reported in smaller rodents, presumablybecause of the high degree of mortality and severe trau-ma that usually result from an attack by a rabid carni-vore; however, Maryland reported a case of rabies in achipmunk (T striatus) in 2001. There has been no doc-umentation of rabies transmission from a rodent to ahuman being.

Additional distributions of ORV (1.67 millionbaits delivered over > 26,000 square miles) were com-pleted during 2001 in Texas to interrupt the transmis-sion of rabies virus in gray foxes and in dogs and coy-otes.18,33,34,d Translocations of animals infected withcanid variants of the rabies virus found in Texas havebeen documented.2,3 These events involved infectedanimals placed in outdoor enclosures prior to release atthe intended location. Rapid responses to these eventsmay have prevented establishment and spread of theinvolved variants.

Rabies in domestic animals decreased 2.4% in2001. Reported cases of rabies in dogs (89 cases) andcattle (82) decreased by 21.9% and 1.2%, respectively;both of these are record-low numbers. Cases of rabiesin cats (270) increased by 8.4% over those reported in2000, whereas rabies among sheep and goats declined70%, from 10 cases in 2000 to 3 cases (representinggoats only) in 2001. Numbers of cases of rabies inhorses/mules reported in 2001 declined 1.9% from 52cases in 2000 to 51 cases in 2001. Cases of rabies weredistributed among 25 states and Puerto Rico. OnlyPuerto Rico (6 cases) and Texas (5 cases) reportedmore than 4 cases of rabies in horses. Continued lownumbers of reported cases of rabies in dogs and cattleattest to the effectiveness of a public health strategyaimed at preventing rabies in domestic animalsthrough spillover from infected wildlife. Vaccinationremains a crucial element in this effort.

In 1999, a study was undertaken to evaluate theepidemiologic features of variants of the rabies virusresponsible for cases of rabies reported in cats and dogsand to assess what contribution, if any, was the resultof bat-associated variants of the rabies virus.35 Nearlyall animals (229 cats and 78 dogs) were infected viaspillover with the predicted terrestrial variant of therabies virus, ie, the variant maintained by and circulat-ed in the dominant terrestrial reservoir species in thegeographic location where the infection occurred. Asingle cat from Maryland was found to be infected witha bat-associated variant of the rabies virus. This impor-tant study lends support to earlier hypotheses basedmainly on small local samples and presumption.

Vaccination of pet animals and livestock that haveregular contact with human beings provides a barrier toprotect human beings from infection with rabies. Thisfact cannot be overemphasized. A single incident involv-ing a case of rabies in a companion species can result inlarge expenditures in dollars and public health efforts toensure that human disease does not occur.36-38 Althoughwidespread vaccination of livestock is neither economi-cally feasible nor justifiable on public health grounds,vaccination of valuable livestock or livestock that mayhave regular contact with human beings in rabies-epi-zootic areas should be considered.30

With the report of 1 human rabies case in 2001,

the total number of cases of rabies diagnosed inhuman beings in the United States since 1990increased to 33. Seven of these 33 (21.2%) individualswere infected outside the United States. Human rabiescases that are the result of infections abroad usuallyoccur in developing nations where rabies in dogs isenzootic, involve regional canine variants of the rabiesvirus, and have a history of dog bite (5/7). Twenty-sixof the 33 (78.8%) individuals were infected with vari-ants of the rabies virus indigenous to the UnitedStates. Monoclonal antibody analysis and geneticsequencing indicated that 24 of these 26 (92.3%) per-sons were infected with variants of the rabies virusassociated with bats (Table 2).5,6 The prevention ofinfection of human beings with rabies virus from bats,although a rare occurrence, remains an importantpublic health concern.31

Rabies in bats is epidemiologically distinct from ter-restrial rabies maintained by carnivores. Understandingof the circulation of variants of the rabies virus in batspecies remains less well developed than that in carni-vores. Successful control of terrestrial rabies in theUnited States through the use of oral vaccines, as hasbeen accomplished in Europe13,39 and southeasternCanada,40 will have no effect on enzootic rabies in batsand the associated risk of human disease.

2002 Rabies UpdateDuring the first 9 months of 2002, no cases of

rabies were reported that were attributable to infec-tion with the raccoon variant of the rabies virus inOhio. Ohio rabies-control programs distribute V-RGbaits on the basis of data gathered via active surveil-lance programs implemented in affected areas and astatewide passive surveillance system. The singlecase of raccoon rabies reported by Ohio in 2001 nearthe Pennsylvania border serves as a reminder thatimmune corridors will not remain so without contin-ued surveillance, as well as cooperation and partici-pation with neighboring states. In Ohio, > 638,000additional doses of ORV baits were distributed dur-ing the late summer-fall of 2002 over a total of >3,200 square miles in 9 eastern Ohio counties(www.odh.state.oh.us/ODHPrograms/ZOODIS/Rabies/Pubs/ORVHIS.PDF; accessed Oct 16, 2002).b

Bait distribution continues along the front of theraccoon rabies epizootic, extending from the shore ofLake Erie in the north, southwest across WestVirginia, through westernmost Virginia, and current-ly terminating in the eastern corner of Tennessee (seemap at www.aphis.usda.gov/mpls/contracts/solicita-tions/6stateswibarriers.PDF; accessed Oct 16, 2002).Rabid raccoons have been reported in several coun-ties in northern Georgia, very close to the Tennesseeborder. Thus, raccoon rabies may soon be detected inKentucky and Tennessee. The risk for introduction ofthe raccoon-associated variant of the rabies virusinto other midwestern states and into routinely ter-restrial rabies-free Mississippi remains a major con-cern.

In Texas, an additional 2.7 million doses of V-RGvaccine were distributed over > 33,000 square milesduring 2002. During the first 9 months of 2002, no



cases of rabies attributable to the dog/coyote variant ofthe rabies virus were reported in Texas. During thissame period, 50 cases of rabies attributable to the vari-ant of the rabies virus associated with gray foxes werereported in foxes and other species; however, no caseswere reported outside of the original ORV treatmentarea. Since the programs were initiated in 1995, almost17.45 million doses of V-RG vaccine have been distrib-

uted over > 255,400 square miles in Texas.d Canadianofficials indicate that the area of Ontario affected by theepizootic of rabies in raccoons has stabilized and thatORV programs are at least partly responsible for thissuccess. Reported cases of rabies associated with a sec-ond focus of the raccoon rabies epizootic in Canadathat originated from the state of Maine and enteredCanada via New Brunswick have decreased in 2002(www.gis.queensu.ca/rreporter; accessed Oct 16,2002).

Three cases of rabies in human beings caused by batvariants of the rabies virus have been reported during2002. California reported a case that was the result ofinfection with the Brazilian free-tailed (T brasiliensis)virus variant, whereas Tennessee and Iowa each report-ed a case that resulted from infection with the variant ofthe rabies virus associated with silver-haired and easternpipistrelle (L noctivagans and P subflavus) bats.6,41,42,e

On Mar 31, 2002, a 28-year-old man residing inGlenn County, Calif, died of rabies. The patient’s fami-ly reported that he had killed a bat in his house earlierthat month. An investigation revealed a bat colony inthe attic of the man’s house.41

On Aug 31, 2002, a 13-year-old boy residing inFranklin County, Tenn, died of rabies. The patient’sparents reported that he had found a bat on the groundduring the previous month and brought it home, priorto releasing it later in the nearby woods.42

On Sept 28, 2002, a 20-year-old man residing inLinn County, Iowa, died of rabies. County health offi-cials tested several dogs with which the patient hadcontact, including one that bit him, but found no evi-dence of rabies in the tested animals.e

A history of bite was indicated for only 1 of thesecases, and the involved dog tested negative for rabiesvirus. The patients either did not notice the actualevents that exposed them to rabies or judged them astoo insignificant to be of any consequence with regardto the possibility of causing rabies infection and forgotabout them. Nonetheless, the most plausible explana-tion for the cause of these cases remains infection viabat bite. These latest cases bring the total number ofcases of rabies diagnosed in human beings in theUnited States since 1990 to 36. Twenty-nine of theseindividuals were infected with variants of the rabiesvirus indigenous to the United States. Monoclonalantibody analysis and genetic sequencing indicatedthat 27 of these 29 (93%) persons were infected withvariants of the rabies virus associated with bats.

aSun B, California Department of Health Services, Sacramento, Calif:Personal communication, 2002.

bSmith KA, Krogwold R, Collart M, Ohio Department of Health,Columbus, Ohio: Personal communication, 2002.

cGuerra MA, Centers for Disease Control and Prevention, Atlanta,Ga: Personal communication, 2002.

dWilson PJ, Texas Department of Health, Austin, Tex: Personal com-munication, 2002.

eCurrier RW, Iowa Department of Public Health, Des Moines, Iowa:Personal communication, 2002.

References1. Smith JS, Orciari LA, Yager PA. Molecular epidemiology of

rabies in the United States. Semin Virol 1995;6:387–400.

Table 2—Cases of rabies in human beings in the United States,by circumstances of exposure and rabies virus variant, 1990through September 2002*

Date of State of Exposure Rabies virusdeath residence history† variant‡

5 Jun 90 TX Bat bite - TX Bat, Tb 20 Aug 91 TX Unknown§ Dog/coyote 25 Aug 91 AR Unknown§ Bat, Ln/Ps 8 Oct 91 GA Unknown§ Bat, Ln/Ps 8 May 92 CA Dog bite - India Dog, India 11 Jul 93 NY Unknown§ Bat, Ln/Ps

9 Nov 93 TX Unknown Bat, Ln/Ps 21 Nov 93 CA Dog bite - Mexico Dog, Mexico 18 Jan 94 CA Unknown Bat, Ln/Ps 21 Jun 94 FL Unknown - Haiti Dog, Haiti 11 Oct 94 AL Unknown§ Bat, Tb 15 Oct 94 WV Unknown§ Bat, Ln/Ps

23 Nov 94 TN Unknown§ Bat, Ln/Ps 27 Nov 94 TX Unknown Dog/coyote 15 Mar 95 WA Unknown§ Bat, Msp 21 Sep 95 CA Unknown§ Bat, Tb 23 Oct 95 CT Unknown Bat, Ln/Ps 9 Nov 95 CA Unknown§ Bat, Ln/Ps

8 Feb 96 FL Dog bite - Mexico Dog, Mexico 20 Aug 96 NH Dog bite - Nepal Dog, SE Asia 15 Nov 96 KY Unknown§ Bat, Ln/Ps 19 Dec 96 MT Unknown Bat, Ln/Ps 5 Jan 97 MT Unknown§ Bat, Ln/Ps 18 Jan 97 WA Unknown§ Bat, Ef

17 Oct 97 TX Unknown§ Bat, Ln/Ps 23 Oct 97 NJ Unknown§ Bat, Ln/Ps 31 Dec 98 VA Unknown Bat, Ln/Ps 20 Sep 00 CA Unknown§ Bat, Tb 9 Oct 00 NY Dog bite - Ghana Dog, Africa 10 Oct 00 GA Unknown§ Bat, Tb

25 Oct 00 MN Bat bite Bat, Ln/Ps 1 Nov 00 WI Unknown§ Bat, Ln/Ps 4 Feb 01 CA Unknown - Philippines§ Dog, Philippines 31 Mar 02 CA Unknown§ Bat, Tb 31 Aug 02 TN Unknown§ Bat, Ln/Ps 28 Sep 02 IA Unknown§ Bat, Ln/Ps

*All laboratory-confirmed cases of rabies in human beings who developedthe disease in the United States, 1990-2002. †Data for exposure history arereported only when the biting animal was available and tested positive forrabies; or when plausible information was reported directly by the patient (iflucid or credible); or when a reliable account of an incident consistent withrabies exposure (eg, dog bite) was reported by an independent witness (usu-ally a family member). ‡Variants of the rabies virus associated with terrestri-al animals in the United States are identified with the names of the reservoiranimal (dog or dog/coyote, in all cases shown), followed by the name of themost definitive geographic entity (usually the country) from which the varianthas been identified. Variants of the rabies virus associated with bats areidentified with the name(s) of the species of bat(s) in which they have beenfound to be circulating. Because information regarding the location of theexposure and the identity of the exposing animal is almost always retro-spective and much information is frequently unavailable, the location of theexposure and the identity of the animal responsible for the infection are oftenlimited to deduction. §In some instances where the exposure history isunknown, there may have been known or inferred interaction that, especial-ly for bats, could have involved an unrecognized bite.

Ln/Ps = Lasionycteris noctivagans or Pipistrellus subflavus, the silver-haired bat or the eastern pipistrelle. Msp = Myotis, species unknown. Tb =Tadarida brasiliensis, the Brazilian (Mexican) free-tailed bat. Ef = Eptesicusfuscus, the big brown bat.



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3. Centers for Disease Control and Prevention. Translocationof coyote rabies—Florida, 1994. MMWR Morb Mortal Wkly Rep1995;44:580–583.

4. Meltzer MI. Assessing the cost and benefits of an oral vac-cine for raccoon rabies: a possible model. Emerg Infect Dis 1996;2:343–349.

5. Noah DL, Drenzek CL, Smith JS, et al. Epidemiology ofhuman rabies in the United States, 1980 to 1996. Ann Intern Med1998;128:922–930.

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12. Smith JS, Orciari LA, Yager PA, et al. Epidemiologic and his-torical relationships among 87 rabies virus isolates determined bylimited sequence analysis. J Infect Dis 1992;166:296–307.

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15. Hanlon CA, Rupprecht CE. The reemergence of rabies. In:Scheld WM, Armstrong D, Hughes JM, eds. Emerging infections 1.Washington, DC: ASM Press, 1998;59–80.

16. Roscoe DE, Holste WC, Sorhage FE, et al. Efficacy of an oralvaccinia-rabies glycoprotein recombinant vaccine in controlling epi-demic raccoon rabies in New Jersey. J Wildl Dis 1998;34:752–763.

17. Robbins AH, Borden MD, Windmiller BS, et al. Preventionof the spread of rabies to wildlife by oral vaccination of raccoons inMassachusetts. J Am Vet Med Assoc 1998;213:1407–1412.

18. Fearneyhough MG, Wilson PJ, Clark KA, et al. Results of anoral rabies vaccination program for coyotes. J Am Vet Med Assoc1998;212:498–502.

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